The present invention relates to superconducting ceramic film structure and manufacturing method for the Same.
Bi-based superconducting ceramics are well-known in the field as high-Tc materials. There are two types of superconducting phases of these ceramics, i.e. a low Tc phase in which Tc is up to 80.degree. K. and a high Tc phase in which Tc is up to 110.degree. K. The low Tc phase is realized by ceramic materials of Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8+Z whose c-axis length is 30 .ANG.. The high Tc phase is realized by ceramic material of Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10+Z whose c-axis length is 36 .ANG..
It is well-known that single crystalline magnesium oxide is suitable for providing a substrate on which Bi-based superconducting ceramic thin and thick films are formed. The radius of magnesium ion, however, is close to that of Cu ion so that the replacement of Cu sites by Mg ions is likely and degrades the superconductivity.